On the northern side of Acropolis rock stands the Erechtheion, the last of the buildings that were built during Pericles' era. It was built during the Peloponnesian war, between 421 and 406 BC.The Erechtheion also housed the marks of Poseidon's Trident and the olive tree of Athena. At the site where the Erechtheion was built there were already some small temples and monuments that were incorporated in the new building. For this reason, the Erechtheion doesn't have the form of a unified temple. Each of the four sides of the temple has a different form. The eastern part of the Erechtheion was probably dedicated to Athens Polias. There they kept the wooden statue of the goddess who, according to the legend, had fallen from the sky. On this statue they placed the new peplos of Athena carried by the Procession of the Panathenaea.
On the northern side of the Erechteion there is a portico with four Ionic columns and one magnificent gate at the background. The southern side also has a portico where the columns are being replaced by the famous statues of girls, called Caryatids. Six slender girls carry a marble basket on their head and at the same time support the roof. The western side of the Erechtheion covers two different levels due to the ground's height difference. The western part was perhaps the most sacred one because it housed the marks of Poseidon's trident and the olive tree of Athena.